Auxiliary decelerator for internalcombustion engines



Oct. 28, 1947. R. GEDSTAD 2,429,714

AUXILIARY DECELERATOR FOR INTERNAL-COMBUSTION ENGINES Filed Dec. 2-1, 1945 2 Sheets-Sheet 1 BY M14; 27

ATTORNEY Oct. 28, 1947. R. GEDSTAD 2,429,714

AUXILIARY DECELERATOR FOR INTERNAL-COMBUSTION ENGINES 1 Filed Dec. 21, 1945 '2 Sheets-Sheet 2 '0IIIIIIIIIIIIIIIIIIIIIIIIIIIIfl) Rue/O 6.4.1 .4

ATTORNEY Patented Oct. 28, 1947 AUXILIARY DECELERATOR FOR INTERNAL- COMBUSTION ENGINES Rudolph Gedstad, Peoria, 111., assignor to Caterpillar Tractor Co., San Leandro, Calif., a corporation of California Application December 21, 1945 Serial No. 636,349

1 Claim. 1

The present invention relates to an auxiliary decelerator for internal combustion engines and particularly to an engine decelerating device which may be operated by foot in conjunction with an engine which is normally accelerated and decelerated through the medium of a manually controlled system.

In many tractors, as well as other types of road grading and earth moving vehicles, there are several hand actuated levers under the operators control. For example, there are, in addition to steering means, various clutches and levers for controlling the movement of the vehicle over the ground and also manually controlled means for raising or lowering a bulldozer blade or other similar earth handling equipment. tion of the engine which drives the vehicle isrcustomarily controlled by a hand throttle capable of being set for any desired engine speed. Frequently, the hand throttle is set at full load position and, due to a change-in operating conditions, the load which the vehicle is handling is reduced calling for an adjustment of the throttle. This may occur while the operator is negotiating a turn or while the vehicle is passing over the crest of a high spot in the terrain or under various other circumstances requiring adjustments occupy both hands of the operator and render it impractical for him to adjust the throttle.

It is desirable, therefore, in order to provide improved operating conditions, that the operator of such a vehicle be able momentarily to decelerate the engine while his hands are otherwise occupied.

It is an object of the present invention to provide in combination with a vehicle having an engine and a manually actuated throttle therefor an auxiliary foot actuated decelerating means. A further object of the inventionris to provide a foot decelerator for an engine normally controlled by a hand throttle which will effect momentary deceleration upon being depressed and which will permit immediate acceleration upon being released without disturbing the position 7 or controlling effect of the hand throttle. Further objects and advantages of the invention are made apparent in the following specification in which reference is made to the accompanying drawings.

The drawings illustrate the invention as applied tothe throttle control system of a compression ignition engine though it will be apparent from reading the following specification that the decelerator of the present invention is applicable to other types of engines.

The operawhich.

In the drawings:

Fig. 1 is a diagrammatic view illustrating the the application thereto of a foot decelerator constructed in accordance with the present invention;

Fig. 2 is an enlarged fragmentary view of the foot decelerator illustrated in Fig. 1 with parts shown in section; and

Fig. 3 is a sectional view taken on line III-III of ;Fig. 2.

The fuel control system illustrated in Fig. 1 comprises a governor assembly generally indicated at 10, a fuel pump housing II, a hand throttle l2 and the foot decelerator mechanism of the present invention generally indicated at 13. A control rod [4 extends through the fuel pump assembly H and, through conventional mechanism, not shown, engages with plungers of pumps l 5 within said assembly in such a manner thatreciprocation of the control rod l4 adjusts the pump plungers to effect the volume of fuel delivered thereby to the cylinders of the engine. The position of the control rod [4 and therefore the volume of fuel delivered to the engine is controlled by the governor mechanism It! engaging the rod M at one end and by a spring l5 engaging the rodat the other end and adjustably tensioned by the throttle l2.

The governor I0 is usually driven by a cam shaft I! of the engine with which it is associated. The cam shaft, through gears indicated at 3 and I9, revolves a pair of governor fiy weights 28 which; are pivotally connected to the gear l9 as by pins 2|. As the gear [9 rotates the fly weights 2!) tend to swing outwardly and fingers 22 thereon engage a flange 23on a slidable sleeve 24. The end of the sleeve 24 has ;a bifurcated portion 25 engaging a lever 26 which swings about a stationary pivot 21 at one end and is pivotally connected at its other end as by a pin 28 with the control rod M. The spring 16 is connected at one end to the control rod l4 and at its opposite end with a rod 29 which is extended as indicated by the broken line in Fig. 1 to a point adjacent the operator's station on the vehicle which is driven by the engine.

The tension on the spring l6 which counterbalances the operation of the governor is under control of the throttle [2 which has a hand lever 30 fixed to a shaft 3|. Also fixed to the shaft 3| is a lever 32 which is pivoted to a connecting rod 33. One end of the connecting rod 33 is pivoted to a bell crank pivotally supported on a pin 35 and the bell crank is also connected with a rod 36 which, through the medium of the foot decelerator mechanism I3 is connected with the rod 29 in a manner presently to be described. The rods 29 and 36 may be considered as a single rod which would be constructed in one piece Were it not for the interposition of the decelerator mechanism I3 of the present invention. The hand throttle operating connections just described form no part of the present invention but are disclosed as typical of conventional control mechanism.

A portion of the rod 29 as illustrated in Figs. 1 and 2 is arranged to underlie the o erators; plat form, a fragment of whichis illustrated at 3T. Directly beneath the platform 31 the rod 23 is connected with the rod 36 by means of thQS tIILLCr, ture illustrated in Fig. 2 wherein therod 29, is

shown as having an elongated cylindrical casing 38 secured to its end as by welding and the rod 35 is shown as having a plunger". 39 with an enlarged head 4E3 thereon" reciprocably disposed within the cylinder 38. A threaded ca'p ll serves as an enclosure for one end of the cylinder 38 and is locked in place by means of a capscrew 42. An expansible coil spring 43 is'dispos'ed within the cylinder 38 and bears at one end against the cap 4| and at its opposite end; against the enlarged head 40. of the plunger 39." The plunger 39 is therefore held by the spring'43 in the position illustrated in Fig. 2 with its head 43 against the end of the cylinder 38 to which the rod; 2-9 is secured. The spring 43 is heavier than the governor controlled spring [6 and is sufficiently heavily loaded that it is not effected upon adjustmentof the hand throttle 12 for establishing the desired tension of. the spring l6 which balances the operation of-the governor. Therefore, in normal operation of the engine under control of the hand throttle, the rods 29 and 36 operate in the manner of a single rod and the auxiliary decelerator has no eiTect. 'Ijhe engine, however, may be quickly decelerated without the necessity of disturbing the position of or in any way moving the hand throttle.

By urging'the cylinder 38 to the left, as viewedin Figs. 1 and 2, against the resistance of the spring 43, the tension on the spring l6 may be reduced to decelerate the engine. This is accomplished by a foot pedal 44; Which extends to a position above the platform 37 where it may be readily depressedby the operators foot. The

foot pedal 44 has a shaft 45 which extends down wardly through the platform and connect's at its lower end with a lever 46. The lever 46 -is keyed to a shaft 4'! which rotates in bearing brackets 63 also secured to the platform 3l'as best shown in Figs. 2 and 3. Also keyed to the shaft 41 for oscillation therewithis abifurcatedlever 49, the

lower ends of which embrace the cylinder 38 and are engageable against a collar 50 which is rigidly secured to the exterior of the cylinder as by welding or the like.

With the construction illustrated, the pressure of the foot pedal 44 efiects swinging of the lever 49 to the left as illustrated in Figs. 1 and 2 and through engagement of the lever with the collar 50 the cylinder 38 and rod 29 are moved in a direction to relieve tension on the spring 16 thus decelerating the engine while the rod 36 and manually controlled throttle to which it is connected are left undisturbed. The deceleration of the engine in this manner, of course, imposes an additirial load on the spring 43 which is compressed and when the operators foot is removed rom the. pedal; .4:; the spring e pands to return the cylinder and the rod 29 to their original position determined by the setting of the hand throttle. The cylinder 38 ispreferably provided with vents asindicated at 5i to admit atmosphere and prevent the creation ofa partial vacuum in the cylinder as it moves with relation to the head 40.

The operator ot a vehicle provided with the deceleratorof the present invention may at any timeeffect immediate deceleration of the engine without the necessity of using: his hands and without the necessity of thereafter resetting; the hand throttle to reestablish the normal engine speed underwhich the vehicle is being: operated.

'I claim-t In. a. vehicle having an engine and an operators. platform, a manually actuated throttle lever adjacentthe platform and connected with the engine bya control rod underlying-the platform, a cylinder on. one portion of said rod, a plungenon another portion of said: rod disposed for. reciprocation in saidcylinder; a spring surrounding the rod and interposed between the cylinder and plunger and maintaining the effective length er the rod-fixed duringmanipula: tion of the manualcontrol; afoot actuated pedal extending-through the platform a lever actuated by said pedal anda collaron saidcylinder engageable by said lever tomove the cylinder and compress the springtherein to effect throttling independently of the; manual control.

aenorrnonnsmn,

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